Photovoltaic cells are known, which include strips of coated materials which form photovoltaic junctions, the coatings being on a glass substrate which may be exposed to sunlight via the uncoated surface of the glass. In order that such cells shall be commercially feasible they must be capable of fabrication in large areas, and they must have high efficiencies in order that their cost of fabrication in dollars and energy consumption may be recouped in a relatively short time, and they must have long life. Efficiency of photovoltaic cells derives in part from efficiency in terms of rate of conversion of sunlight to electrical energy, in terms of electrical losses within the cells and in the connections which must be made with the outside world, and in area efficiency, i.e., the proportion of the system area which is devoted to production of energy is a function of total area of glass, taking into account that some part of the glass surface must be devoted to leads and not to active photovoltaic area. In the type of cell here contemplated, the cadmium sulphide cell, strips of cadmium sulphide are applied to a tin oxide coating previously applied to a glass surface. The cadmium sulphide layer may be about 2 microns thick. Over the cadmium sulphide layer is deposited, as by electrodeposition, a layer of copper sulphide, which forms a heterojunction with the cadmium sulphide. Electrodes are deposited on the copper sulphide, and the spaces between the strips are provided with elongated electrodes extending along the channels. These channels are necessary but they do not contribute to power output. Electricity must flow through the channels, and in so doing introduces electrical losses. Therefore, the tin oxide must have low resistivity, i.e., ohms per square. But, also the total current path lengths must be maintained small, so that the widths of the active layers of the cell are limited by considerations of electrical efficiency. Light which falls on the channels is wasted, and this reduces output per square of glass, everything else being equal. Pursuant to present design about 15% of light flux is wasted. The latter waste can be in major part avoided by providing a diffusing surface superposed over the channels, and such surfaces can be readily formed by etching or sand blasting the glass surface where diffusion is required. The diffusing surface refracts about 75% of the sunlight, which would otherwise fall on the inactive areas of the cell, to the active areas.